PDF document of 5.14 MB covering 5 pin, 6 pin and 8 pin regulators, apparently a reference collection of pinouts or circuits for small voltage regulators and PWM controllers rather than a single board schematic. The name gives no device or brand. Such references help when identifying an unmarked regulator on a motherboard or graphics card, checking which pin is enable, feedback or output, and measuring expected voltages during a power fault diagnosis. Always confirm the part marking against the manufacturer datasheet before replacing it.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @datasheets1. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.